Electric fan

ABSTRACT

The present invention provides an electric fan capable of blowing cool wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter. The electric fan of the present invention comprises: a housing having a suction port for air and a blowing port for air; an axial flow fan for suctioning air from the suction port into the housing and for blowing the suctioned air from the blowing port; an evaporation filter for passing the air suctioned from the suction port; a water supplying system capable of supplying water to the evaporation filter; an indirect heat exchanger for cooling the air passed through the evaporation filter, the indirect heat exchanger being disposed downstream from the evaporation filter; and a cooler for cooling a coolant for the indirect heat exchanger; wherein the suction port and the blowing port are formed on the same side surface of the housing; and wherein the blowing port is formed on the central part of the side surface of the housing, and the suction port is formed on the outer edge part of the blowing port.

FIELD OF THE INVENTION

The present invention relates to an electric fan for blowing cool windby utilizing vaporization heat of water contained in an evaporationfilter.

BACKGROUND ART

Although electric fans simply create a flow of air, the created flow ofair blows off air heated on a surface of a person's human body, andthereby the person feels that the air from the electric fan is cool.However, since the electric fan basically does not have a function ofdecreasing the temperature of air, when the temperature of the air istoo high, the person no longer feels that the air is cool.

Therefore, an electric fan blowing cool wind by utilizing thevaporization heat of water to actively decrease the temperature of air,which is referred to as a cool wind fan, is used. More specifically, anevaporation filter is disposed in a path of air, and water is suppliedto the evaporation filter. When the air passes through the evaporationfilter containing water, the water contained in the evaporation filteris evaporated, and the air is deprived of the vaporization heat requiredfor the vaporization of water, whereby the air is cooled.

In this kind of the cool wind fan, the water supplied beyond thewater-retaining capacity of the evaporation filter falls from theevaporation filter into a tank, which results in making unpleasant soundcontinuously. Patent Documents 1 and 2 disclose methods for preventingthe unpleasant sound.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP 05-93525 A

Patent Document 2: JP 2008-138932 A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, when the electric fan is a large flow rate fan having a largeblade diameter, which is used in a wide space such as a gymnasium, afactory, and a warehouse, or used for outdoor space, warm air is notsufficiently cooled and the warm air may still be blown even if thevaporization heat of water is utilized.

Accordingly, an object of the present invention is to provide anelectric fan capable of blowing cool wind efficiently even if theelectric fan is a large flow rate fan having a large blade diameter.

Means for Solving the Problems

An electric fan according to the present invention comprises:

a housing having a suction port for air and a blowing port for air;

an axial flow fan for suctioning air from the suction port into thehousing and for blowing the suctioned air from the blowing port;

an evaporation filter for passing the air suctioned from the suctionport;

a water supplying system capable of supplying water to the evaporationfilter;

an indirect heat exchanger for cooling the air passed through theevaporation filter, the indirect heat exchanger being disposeddownstream from the evaporation filter; and

a cooler for cooling a coolant for the indirect heat exchanger;

wherein the suction port and the blowing port are formed on the sameside surface of the housing; and

wherein the blowing port is formed on the central part of the sidesurface of the housing, and the suction port is formed on the outer edgepart of the blowing port.

Effect of the Invention

The present invention can provide an electric fan capable of blowingcool wind efficiently even if the electric fan is a large flow rate fanhaving a large blade diameter.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing an inner structure of an electric fanaccording to one embodiment of the present invention.

FIG. 2 is a front view showing an appearance of an electric fanaccording to one embodiment of the present invention.

FIG. 3 is a side view showing an appearance of an electric fan accordingto one embodiment of the present invention.

FIG. 4 is a back view showing an appearance of an electric fan accordingto one embodiment of the present invention.

FIG. 5 is an enlarged view showing a configuration of a hot winddischarger.

MODE FOR CARRYING OUT THE INVENTION

The electric fan of the present invention is an electric fan blowingcool wind by utilizing the vaporization heat of water contained in anevaporation filter. The electric fan of the present invention can blowcool wind efficiently even if the electric fan is a large flow rate fanhaving a large blade diameter. The inner structure of the electric fanaccording to one embodiment of the present invention is shown in FIG. 1,and the appearance of the electric fan according to one embodiment ofthe present invention is shown in FIGS. 2 to 4. In this electric fan, asuction port 11 for air and a blowing port 12 for air are formed on thefront part of a housing 10, and an axial flow fan 20 is mounted insidethe housing 10.

The housing 10 may be made from a plastic or may be made from afiber-reinforced plastic (FRP). At least the inner surface of thehousing 10 is preferably made from a heat insulating material such as aplastic foam in terms of the prevention of the temperature increaseinside the housing 10 due to the ambient temperature. The position ofthe suction port 11 and the blowing port 12 on the housing 10 can besuitably selected depending on the purpose. For example, the suctionport 11 can be formed on one side surface of the housing 10, and theblowing port 12 can be formed on the opposed side surface of the housing10. However, in this case, warm air before cooling is continuouslysuctioned from the suction port 11. In particular, for a large flow ratefan having a large blade diameter, the warm air is not sufficientlycooled and the warm air may still be blown from the blowing port 12.

Therefore, as shown in FIG. 2, it is important that the suction port 11and the blowing port 12 are formed on the same side surface of thehousing 10. In this way, a part of cool air blown from the blowing port12 is suctioned from the suction port 11 again, and thereby the airblown from the blowing port 12 becomes cooler. In particular, for alarge flow rate fan having a large blade diameter, this configuration asdescribed above is effective because it is difficult to cool the warmair instantaneously. Further, in terms of downsizing the electric fan,it is also important that the blowing port 12 is formed on the centralpart of one side surface of the housing 10 and that the suction port 11is formed on the outer edge part of the blowing port 12, as shown inFIGS. 2 to 4. The electric fan having this configuration can cool aireffectively even if the electric fan is a large flow rate fan having alarge blade diameter.

The axial flow fan 20 is mounted in the middle of the flow channelbetween the suction port 11 and the blowing port 12. The axial flow fan20 is a fan for suctioning air from the suction port 11 into the housing10 and for blowing the suctioned air from the blowing port 12. Asdescribed above, the structure of the electric fan according to thepresent invention is suitable for a large flow rate fan having a largeblade diameter. More specifically, the blade diameter of the axial flowfan is preferably 20 to 50 inches, and is more preferably 24 to 36inches. In addition, the flow rate of air is preferably 3500 to 35000m³/h in operation, and is more preferably 5000 to 25000 m³/h. The motorfor rotating the axial flow fan 20 may be an internal motor in the axialflow fan 20, or any other non-internal motor may be mounted to rotatethe axial flow fan 20 via a belt and a pulley. In the latter case, therotational frequency of the axial flow fan 20 can be adjusted by using agear.

In the electric fan of the present invention, an evaporation filter 30is mounted for passing the air suctioned from the suction port 11, asshown in FIG. 1. The evaporation filter 30 is mounted in a flow channelbetween the suction port 11 and the blowing port 12. The evaporationfilter 30 is typically disposed upstream from the axial flow fan 20. Theevaporation filter 30 may be made from a paper such as a corrugatedcardboard, or from a plastic such as an open-cell polyurethane foam or asintered polyethylene material. Since water is introduced to theevaporation filter 30, the evaporation filter 30 is preferably subjectedto a treatment for improving the hydrophilicity, in particular when theevaporation filter 30 is made from a plastic.

In the electric fan of the present invention, by using a water supplyingsystem 40 having a tank 41 and the water supplying pipe 42, water issupplied (sprinkled) from a water sprinkler 42 a formed on a watersupplying pipe 42 disposed over the evaporation filter 30 to theevaporation filter 30, as shown in FIG. 1. That is, the water in thetank 41 is suctioned to the water supplying pipe 42 with a pump (notshown) mounted in the tank 41, and is supplied from the water sprinkler42 a, which is formed over the evaporation filter 30, to the evaporationfilter 30. In this way, water can be introduced to the evaporationfilter 30 by supplying water from above of the evaporation filter 30.When the air suctioned from the suction port 11 passes through theevaporation filter 30 containing water, the water contained in theevaporation filter 30 is evaporated, and the air is deprived of thevaporization heat required for the vaporization of water, whereby theair is cooled. Additionally, Ag ion ceramic balls can be put in a box 48mounted in the tank 41 containing water, to suppress the generation ofbacteria and to perform air cleaning function. By using a bactericidallamp instead of the Ag ion ceramic balls, the generation of bacteria canbe suppressed and air cleaning function can be performed as well. Theposition of the bactericidal lamp mounted may be in the tank 41 or maybe in the middle of the water supplying pipe 42.

In the electric fan of the present invention, a pre-evaporation filter35 for passing the air suctioned from the suction port 11 is preferablymounted upstream from the evaporation filter 30, as shown in FIG. 1. Asfor the mounted position of the pre-evaporation filter 35, thepre-evaporation filter 35 is mounted in the middle of the flow channelbetween the suction port 11 and the evaporation filter 30. Thepre-evaporation filter 35 may be made from a paper such as a corrugatedcardboard, or from a plastic such as an open-cell polyurethane foam oran sintered polyethylene material. Since water is introduced to thepre-evaporation filter 35, the pre-evaporation filter 35 is preferablysubjected to a treatment for improving the hydrophilicity, in particularwhen the pre-evaporation filter 35 is made from a plastic.

Preferably, by using the water supplying system 40, water is supplied(sprinkled) from a water sprinkler 42 b formed on a water supplying pipe42 disposed over the pre-evaporation filter 35 to the pre-evaporationfilter 35, as shown in FIG. 1. That is, the water in the tank 41 issuctioned to the water supplying pipe 42 with a pump (not shown) mountedin the tank 41, and is supplied from the water sprinkler 42 b, which isformed over the pre-evaporation filter 35, to the pre-evaporation filter35. In this way, water can be supplied from above of the pre-evaporationfilter 35, and water can be introduced to the pre-evaporation filter 35.When the air suctioned from the suction port 11 passes through thepre-evaporation filter 35 containing water, the water contained in thepre-evaporation filter 35 is evaporated, and the air is deprived of thevaporization heat required for the vaporization of water, whereby theair is cooled.

By mounting the pre-evaporation filter 35 upstream from the evaporationfilter 30 in this way, the air reaching the evaporation filter 30 can bepreviously cooled. In addition, the evaporation filter 30 is not exposedin the suction port 11, and therefore the evaporation filter 30 is notheated, for example, by sunlight coming through the suction port 11. Asa result, the cooling efficiency of the air by the evaporation filter 30can be improved.

The water supplied by using the water supplying system 40 may be waterat ordinary temperature, or water cooled with a chiller. For example,water can be cooled by adding an immersion chiller 45 in a cooling unit46 connected to the water supplying pipe 42, as shown in FIG. 1. In thiscase, by making a tube between the tank 41 and the cooling unit 46thicker than the other part, the water tends to remain in the coolingunit 46, and thereby the cooling efficiency can be improved.Alternatively, by using a plurality of chillers 45, immersion chillerscan respectively be added in a plurality of areas formed by partitioningthe tank 41.

As the chiller 45, a relatively small chiller having an electric powerfor cooling of 1 to 10 kW can be used. Although heat is generated in thechiller 45, the heat can be dissipated, for example, by mounting a heatdissipating fan 16 a on the rear surface of the housing 10 of theelectric fan.

The water which is supplied to the evaporation filter 30 or thepre-evaporation filter 35 but is not evaporated is preferably returnedto the tank 41. In order to allow water exchange in the tank 41, a draincock for draining off water in the tank 41 is preferably mounted on thelower part of the housing 10, for example.

Water may be supplied to the evaporation filter 30 and thepre-evaporation filter 35 by the water supplying system 40 continuouslyor intermittently. Before stopping the electric fan, the evaporationfilter 30 and the pre-evaporation filter 35 may be dried withoutsupplying water. The growth of mold can be prevented by drying theevaporation filter 30 and the pre-evaporation filter 35. The electricfan preferably has a function of adjusting the speed of supplying waterin order to adjust the temperature of air. In addition, for drying theevaporation filter 30 and the pre-evaporation filter 35, a drying fan 15can be mounted in the flow channel between the evaporation filter 30 andthe pre-evaporation filter 35, for example. In this case, by rotatingthe drying fan 15 for about 1 hour by using a timer after the switch ofthe electric fan is turned off, the growth of mold in the evaporationfilter 30 and the pre-evaporation filter 35 can be prevented.

In the electric fan of the present invention, a dustproof filter or anair cleaning filter may be mounted upstream from the evaporation filter30 or the pre-evaporation filter 35, for example. In this way, the lifeof the evaporation filter 30 or the pre-evaporation filter 35 can beincreased, and clean air is discharged from the blowing port 12.Additionally, the evaporation filter 30 or the pre-evaporation filter 35may have a function of dustproofing and air cleaning. Further, apre-filter made from a polyester or a modacrylic fiber may be mounted inthe suction port 11.

In the electric fan of the present invention, a cooling coil 50 that isan indirect heat exchanger for cooling the air passed through theevaporation filter 30 is mounted downstream from the evaporation filter30, as shown in FIG. 1. Additionally, a cooler (chiller 51) is mountedfor cooling a coolant flowing inside the cooling coil.

The cooling efficiency of air by the evaporation filter 30 is affectedby the temperature of the air suctioned (ambient temperature) and thetemperature of the water introduced to the evaporation filter 30. Whenthe ambient temperature is increased, not only the temperature of theair suctioned from the suction port 11 but also the temperature of thewater in the tank 41 are increased, whereby it becomes difficult to coolair to a desired temperature. This is particularly notable for the largeflow rate fan having a large blade diameter, and a person does not feelcool from the air blown from the blowing port 12 so much when theambient temperature is increased. On the other hand, as the presentinvention, by mounting a cooling coil 50 downstream from an evaporationfilter 30 and by flowing a coolant cooled forcibly with a chiller 51inside the cooling coil 50, a person easily feels cool from the airblown from a blowing port 12 even if the ambient temperature isincreased. Further, as described above, by forming at least an innersurface of a housing 10 with a heat insulating material and by mountingthe evaporation filter 30 (and a pre-evaporation filter 35) and a tank41 inside the housing 10, the temperature increase of the water in theevaporation filter 30 (and the pre-evaporation filter 35) or the tank 41can be suppressed. In a traditional electric fan having an evaporationfilter, the evaporation filter is exposed to the outside. In particularwhen the electric fan is used for outdoor space or at a buildingentrance, sunlight directly illuminates the exposed part of theevaporation filter, and then the temperature of the water in theevaporation filter and the tank is greatly increased. However, in theconfiguration of the present invention as described above, the electricfan is not sensitive to the ambient temperature and the direct sunlight.

Specific examples of the indirect heat exchanger include multi-tubularheat exchangers, coiled heat exchangers, plate heat exchangers, andspiral heat exchangers, and a heat exchanger used can be suitablyselected depending on the cooling performance. As the chiller 45, forexample, a relatively small chiller having an electric power for coolingof 1 to 10 kW can be used. Although the water cooled at about 2° C. isdischarged from the chiller 51, the water is heated to 10° C. or higherby the cooling coil 50, and therefore the problem of water condensatedoes not tend to occur. Although heat is generated in the chiller 51,the heat can be dissipated, for example, by mounting a heat dissipatingfan 16 a on the rear surface of the housing 10 of the electric fan.

In the electric fan of the present invention, a mist sprayer 60 ispreferably mounted on the peripheral of the blowing port 12 downstreamfrom the axial flow fan 20, as shown in FIG. 1. In this way, mist can beintroduced into air, and eventually, the feeling temperature of the coolwind which is blown from the blowing port 12 can be decreased.

The electric fan of the present invention having the configuration asdescribed above can blow cool wind efficiently even if the electric fanis a large flow rate fan having a large blade diameter.

Although the main object of the electric fan of the present invention isto perform cooling function as well as blowing function of air, theelectric fan may be configured to perform heating function by switchinginstead of cooling function. In this case, the indirect heat exchangermounted can be utilized effectively. That is, by mounting a heater 52for heating a heat medium flowing inside the indirect heat exchanger,the air passing through the indirect heat exchanger can be heated.Additionally, an external heater (an electric heater 80 in FIG. 1) canbe mounted in the flow channel of air for heating the air directly.

In order to achieve more effective heating function, the electric fanpreferably has a hot wind generator 70, and a hot wind discharger 71which is mounted so that the hot wind from the hot wind generator 70 isdischarged along the rotation direction of the air from the axial flowfan 20. The hot wind discharger 71 is preferably mounted downstream fromthe axial flow fan. In this way, hot wind at about 350° C., for example,which is generated from the hot wind generator 70 is discharged in acondition that hot wind is easily mixed to the flow of air, and therebythe heating efficiency of air is increased. As the hot wind generator70, a hot wind generator having an electric power for heating of 5 to 15kW can be used, for example. Although heat is generated around the hotwind generator 70, the heat can be dissipated, for example, by mountinga heat dissipating fan 16 b on the rear surface of the housing 10 of theelectric fan.

One specific configuration of the hot wind discharger 71 is that a hotwind discharging hole 71 b is formed on a ring-shaped tube 71 a and thata baffle 71 c is mounted on the periphery of the hot wind discharginghole 71 b so that the hot wind is discharged along the rotationdirection of the ring, as shown in FIG. 5 as the enlarged view. Thering-shaped tube 51 a that is the hot wind discharger 71 is disposedcoaxially with the axial flow fan 20. In this way, when the hot windgenerated from the hot wind generator 70 is discharged from the hot winddischarging hole 71 b on the ring-shaped tube 71 a, the hot wind isdirected to the rotation direction of the air from the axial flow fan 20by the effect of the baffle 71 c. Therefore, the hot wind is dischargedin a condition that the hot wind is easily mixed to the flow of air, andthereby the heating efficiency of air is increased.

When the electric fan is operated as a heater, water is not typicallysupplied to the evaporation filter 30 or the pre-evaporation filter 35.However, water may be supplied to the evaporation filter 30 or thepre-evaporation filter 35. If water is supplied to the evaporationfilter 30 or the pre-evaporation filter 35, the heating efficiency isdecreased but the air can be humidified. Additionally, Ag ion ceramicballs can be put in a box 48 mounted in the tank 41 containing water, tosuppress the generation of bacteria and to perform air cleaningfunction. By using a bactericidal lamp instead of the Ag ion ceramicballs, the generation of bacteria can be suppressed and air cleaningfunction can be performed as well. The position of the bactericidal lampmounted may be in the tank 41 or may be in the middle of the watersupplying pipe 42.

The electric fan having the configuration as described above can blowwarm wind efficiently even if the electric fan is a large flow rate fanhaving a large blade diameter.

For example, a caster with rock mechanism may be mounted on the lowerpart of the housing 10 of the electric fan of the present invention, toobtain a movable electric fan. Additionally, the electric fan may have aconfiguration in which accessories such as switches for operating theelectric fan of the present invention can be retracted inside, to obtainan all-weather electric fan.

DESCRIPTION OF THE REFERENCE NUMERALS

10 housing

11 suction port

12 blowing port

15 drying fan

16 a heat dissipating fan

16 b heat dissipating fan

20 axial flow fan

30 evaporation filter

35 pre-evaporation filter

40 water supplying system

41 water tank

42 water supplying pipe

42 a water sprinkler

42 b water sprinkler

45 chiller

46 cooling unit

48 box

50 cooling coil

51 chiller

52 heater

60 mist sprayer

70 hot wind generator

71 hot wind discharger

71 a ring-shaped tube

71 b hot wind discharging hole

71 c baffle

80 electric heater

1. An electric fan, comprising: a housing having a suction port for airand a blowing port for air; an axial flow fan for suctioning air fromthe suction port into the housing and for blowing the suctioned air fromthe blowing port; an evaporation filter for passing the air suctionedfrom the suction port; a water supplying system capable of supplyingwater to the evaporation filter; an indirect heat exchanger for coolingthe air passed through the evaporation filter, the indirect heatexchanger being disposed downstream from the evaporation filter; and acooler for cooling a coolant for the indirect heat exchanger; whereinthe suction port and the blowing port are formed on the same sidesurface of the housing; and wherein the blowing port is formed on thecentral part of the side surface of the housing, and the suction port isformed on the outer edge part of the blowing port.
 2. The electric fanaccording to claim 1, further comprising: a pre-evaporation filter forpassing the air suctioned from the suction port, the pre-evaporationfilter being disposed upstream from the evaporation filter; wherein thewater supplying system can supply water to the pre-evaporation filter.3. The electric fan according to claim 1, further comprising: a mistsprayer disposed on the peripheral of the blowing port.
 4. The electricfan according to claim 1, wherein the axial flow fan has a bladediameter of 20 to 50 inches.
 5. The electric fan according to claim 1,wherein the flow rate of air in operation is 3500 to 35000 m³/h.
 6. Theelectric fan according to claim 2, further comprising: a mist sprayerdisposed on the peripheral of the blowing port.
 7. The electric fanaccording to claim 2, wherein the axial flow fan has a blade diameter of20 to 50 inches.
 8. The electric fan according to claim 2, wherein theflow rate of air in operation is 3500 to 35000 m³/h.
 9. The electric fanaccording to claim 3, wherein the axial flow fan has a blade diameter of20 to 50 inches.
 10. The electric fan according to claim 3, wherein theflow rate of air in operation is 3500 to 35000 m³/h.
 11. The electricfan according to claim 6, wherein the axial flow fan has a bladediameter of 20 to 50 inches.
 12. The electric fan according to claim 6,wherein the flow rate of air in operation is 3500 to 35000 m³/h.